In recent times soft sided insulated containers have become popular for carrying either articles that may best be served cool, such as beverages or salads, or warm, such as appetizers, hot dogs, and so on. Such containers are frequently used to carry liquids, whether hot liquids, such as soup containers, coffee or tea, or cold liquids such as beer pop, juices and milk. The containers are typically made in a generally cube like shape, whether of sides of equal length or not, having a base, four upstanding walls, and a top. The top is generally a lid which opens to permit articles to be placed in, or retrieved from, the container.
By the nature of their use, it is advantageous for the containers to be water tight. That is, whether to hold melted run-off from ice cubes or to hold spilled liquids, the container must be sufficiently liquid tight that it does not leave a trail of drips, or become moist or sticky to the touch of a person carrying the container.
The present inventor has found it disadvantageous to try to seal the container itself. The type of insulating wall used by the present inventor is generally sewn at its seams. Sewn seams have a tendency to leak at the stitches. Another approach is to fold the insulated blanket from which the container is made, to present an assembly that, through folding, has no seams. This is also disadvantageous, in the present inventor's view, because the insulated blanket used to form the container walls is relatively thick. The thick material does not fold well, in the inventor's view. It would be preferable to form an impermeable layer that has a relatively thin wall thickness so that the resulting product does not look bulky and cumbersome.
It is also advantageous to be able to clean the inside of the insulated container. Spilt liquids may not always have the most attractive air when allowed to dry, and may cause the inside of the container to become unsightly. It is possible to provide a plastic liner for soft sided insulated containers. A see through plastic liner can be made of the minimum amount of material by using only a single layer, and forming seams where the edges of the material meet. A common method of forming such a seam is to weld two adjacent edges together by heating. However, an existing liner of this type is known to have had a tendency for the heat welded seams to develop leaks over time. It would be advantageous to reduce or eliminate the number of heat welded seams formed in areas of the liner that may need to be water tight.
In general, manufacture of an assembly of this type emphasizes cost reduction. One common source of cost savings is a reduction of the raw material used. However, the present inventor has observed, counter-intuitively, that the overall benefit an increase in raw material use can outweigh the cost saving that would otherwise be achieved. Unexpectedly, the use of a greater amount of material in a folded assembly has been found to be advantageous, and has eliminated the need to have a heat welding station in manufacture.